• 제목/요약/키워드: Growth velocity

검색결과 488건 처리시간 0.028초

Improving Adherence to Growth Hormone (GH) Therapy via EasypodTM May Help Maximize the Treatment Outcome

  • Choi, Hae-Jeong
    • Journal of mucopolysaccharidosis and rare diseases
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    • 제1권1호
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    • pp.19-22
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    • 2015
  • In Growth Hormone (GH) therapy, suboptimal adherence is a common problem, reaching up to 82%, and there is a need for interventions to improve adherence and to maximize patients' growth potential eventually. Current studies have demonstrated the association between the rate of non-adherence and reduced height velocity. In order to maximize patients' potential to grow, an auto-injecting/recording device, such as $easypod^{TM}$, may help improve adherence and optimize the treatment effects of GH therapy. The use of $easypod^{TM}$ has contributed to high adherence rates: 87.5% and 93% in Bozzola et al.'s study and the $Easypod^{TM}$ Connect Observational study (ECOS), respectively. Improvement of adherence by $easypod^{TM}$ may lead to higher growth rates of patients receiving GH therapy. Additionally, patients' positive acceptability of $easypod^{TM}$ suggests $easypod^{TM}$ is a preferred device by patients for better adherence.

대향류 에틸렌/공기 비예혼합 화염의 구조 및 Soot 생성 메커니즘 해석 (Numerical Analysis for the Detailed Structure and the Soot Formation Mechanism in Counterflow Ethylene-Air Nonpremixed Flame)

  • 임효준;김후중;김용모
    • 한국자동차공학회논문집
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    • 제7권5호
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    • pp.40-54
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    • 1999
  • The flame structure and soot formation in the counterflow Ethylene-Air nonpremixed flame are numerically analyzed. The present soot reaction mechanism involves nucleation, surface growth, particle coagulation, and oxidation steps. The gas phase chemistry and the soot nucleation, surface growth reactions are coupled by assuming that the nucleation and soot mass growth has the certain relationship with the concentration of benzene and acetylene. In terms of the centerline velocity and the soot volume fraction, the predicted results are compared with the experimental data. The detailed discussion has been made for the sensitivity of model constants and the deficiencies of the present model. Numerical results indicated that the acetylene addition to the soot surface plays the dominant role in the soot mass growth for the counterflow nonpremixed flame.

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고온 필라멘트 다이아몬드 CVD에서 기체유동변수가 결정성장에 미치는 영향 (Effects of Gas Flow Variables on the Crystal Growth of Diamond in Hot Filament-Assisted CVD)

  • 서문규;이지화
    • 한국세라믹학회지
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    • 제31권1호
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    • pp.88-96
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    • 1994
  • Hot filament-assisted CVD was carried out to deposit diamond films on Si(100) substrate at 90$0^{\circ}C$ using a 1% CH4-H2 mixture gas. Deposition was made at various conditions of mass flow rate of the feed gas (30~1000 sccm), pressure (2.5~300 Torr), and filament-substrate distance (4~15 mm), and the deposited films were characterized by SEM, XRD, and Raman spectroscopy. As the flow rate increases, the growth rate also increased but the crystallinity of the film was degraded. A longer filament-substrate distance simply caused both the growth rate and the crystallinity to become poorer. On the other hand, the pressure variation resulted in a maximum growth rate of 2.6 ${\mu}{\textrm}{m}$/hr at 10 Torr and the best film quality around 50 Torr, exhibiting an optimum condition. The observed trends were interpreted in terms of the flow velocity-dependent pyrolysis reaction efficiency and mass transport through the boundary layer.

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Study on simultaneous heat and mass transfer during the physical vapor transport of Hg2Br2 under ㎍ conditions

  • Kim, Geug Tae
    • 한국결정성장학회지
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    • 제29권3호
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    • pp.107-114
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    • 2019
  • A computational analysis has been carried out to get a thorough and full understanding on the effects of convective process parameters on double-diffusive convection during the growth of mercurous bromide ($Hg_2Br_2$) crystals on earth and under ${\mu}g$ conditions. The dimensional maximum magnitude of velocity vector, ${\mid}U{\mid}_{max}$ decreases much drasticlly near Ar = 1, and, then since Ar = 2, decreases. The ${\mu}g$ conditions less than $10^{-2}g$ make the effect of double-diffusion convection much reduced so that adequate advective-diffusion mass transfer could be obtained.

The intrinsic instabilities of fluid flow occured in the melt of Czochralski crystal growth system

  • Yi, Kyung-Woo;Koichi Kakimoto;Minoru Eguchi;Taketoshi Hibiya
    • 한국결정성장학회:학술대회논문집
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    • 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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    • pp.179-200
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    • 1996
  • The intrinsic instabilities of fluid flow occurred in the melt of the Czochralski crystal growth system Czochralski method, asymmetric flow patterns and temperature profiles in the melt have been studied by many researchers. The idea that the non-symmetric structure of the growing equipment is responsible for the asymmetric profiles is usually accepted at the first time. However further researches revealed that some intrinsic instabilities not related to the non-symmetric equipment structure in the melt could also appear. Ristorcelli had pointed out that there are many possible causes of instabilities in the melt. The instabilities appears because of the coupling effects of fluid flow and temperature profiles in the melt. Among the instabilities, the B nard type instabilities with no or low crucible rotation rates are analyzed by the visualizing experiments using X-ray radiography and the 3-D numerical simulation in this study. The velocity profiles in the Silicon melt at different crucible rotation rates were measured using X-ray radiography method using tungsten tracers in the melt. The results showed that there exits two types of fluid flow mode. One is axisymmetric flow, the other is asymmetric flow. In the axisymmetric flow, the trajectory of the tracers show torus pattern. However, more exact measurement of the axisymmetrc case shows that this flow field has small non-axisymmetric components of the velocity. When fluid flow is asymmetric, the tracers show random motion from the fixed view point. On the other hand, when the observer rotates to the same velocity of the crucible, the trajectory of the tracer show a rotating motion, the center of the motion is not same the center of the melt. The temperature of a point in the melt were measured using thermocouples with different rotating rates. Measured temperatures oscillated. Such kind of oscillations are also measured by the other researchers. The behavior of temperature oscillations were quite different between at low rotations and at high rotations. Above experimental results means that the fluid flow and temperature profiles in the melt is not symmetric, and then the mode of the asymmetric is changed when rotation rates are changed. To compare with these experimental results, the fluid flow and temperature profiles at no rotation and 8 rpm of crucible rotation rates on the same size of crucible is calculated using a 3-dimensional numerical simulation. A finite different method is adopted for this simulation. 50×30×30 grids are used. The numerical simulation also showed that the velocity and flow profiles are changed when rotation rates change. Futhermore, the flow patterns and temperature profiles of both cases are not axisymmetric even though axisymmetric boundary conditions are used. Several cells appear at no rotation. The cells are formed by the unstable vertical temperature profiles (upper region is colder than lower part) beneath the free surface of the melt. When the temperature profile is combined with density difference (Rayleigh-B nard instability) or surface tension difference (Marangoni-B nard instability) on temperature, cell structures are naturally formed. Both sources of instabilities are coupled to the cell structures in the melt of the Czochralski process. With high rotation rates, the shape of the fluid field is changed to another type of asymmetric profile. Because of the velocity profile, isothermal lines on the plane vertical to the centerline change to elliptic. When the velocity profiles are plotted at the rotating view point, two vortices appear at the both sides of centerline. These vortices seem to be the main reason of the tracer behavior shown in the asymmetric velocity experiment. This profile is quite similar to the profiles created by the baroclinic instability on the rotating annulus. The temperature profiles obtained from the numerical calculations and Fourier transforms of it are quite similar to the results of the experiment. bove esults intend that at least two types of intrinsic instabilities can occur in the melt of Czochralski growing systems. Because the instabilities cause temperature fluctuations in the melt and near the crystal-melt interface, some defects may be generated by them. When the crucible size becomes large, the intensity of the instabilities should increase. Therefore, to produce large single crystals with good quality, the behavior of the intrinsic instabilities in the melt as well as the effects of the instabilities on the defects in the ingot should be studied. As one of the cause of the defects in the large diameter Silicon single crystal grown by the

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모유양양아와 인공영양아의 성장발육 상태에 관한 횡단적 연구 (Cross-sectional Study of Growth of Korean Breast Fed Formula Fed Infants from 1 to 3 Postpartum Months)

  • 최경숙;최혜미;정상진;구재옥;임현숙
    • 대한지역사회영양학회지
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    • 제2권1호
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    • pp.3-12
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    • 1997
  • One-to three -month-old infants(n=252) were compared their growth performance(weight, length, head circumference, chest circumference) by feeding methods in cross-sectional study. There were two groups : breast-fed(BF) and formula-fed groups(FF). The weights of infants at 1, 2, and 3 postpartum month were 4.50$\pm$0.48kg, 5.76$\pm$0.62kg and 6.67$\pm$0.68kg, respectively. The weigh of male infants was higher than females. The length were 53.7$\pm$2.6cm, 57.4$\pm$3.3cm, 61.1$\pm$3.1cm at one to three postpartum months, respectively. The length of male infants was higher than females, too. Overall there were no significant differences between feeding methods in weight, length, head and chest circumferences, and monthly weight and length velocity. But 3-month-old formula-fed male infants showed bigger significantly in weight, monthly weight velocity and chest circumference than the breast-feds. By Korean standards, weight-for-height Z-score were distributed from 0 to +2. Not only was there a few malnourished infants but also overnourished were noticed, especially in formula-fed group. From this survey, long-time survey on growth and development of large scales might be necessary to determine the effect of feeding methods of infants after 3 months and to set proper grwoth standard for infant. And it was suggested the that the careful attention of polarized nutritional problems of early infants was needed, especially in formula-fed group. (Korean J Community Nutrition 2(1) : 3~12, 1997)

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초지화재 발생시 바람의 속도 및 초본의 높이가 화염전파에 미치는 영향에 대한 수치해석적 연구 (A Numerical Study on the Effects of the Wind Velocity and Height of Grassland on the flame Spread Rate of Forest Fires)

  • 배승용;김동현;유홍선;이성혁
    • 한국화재소방학회논문지
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    • 제22권3호
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    • pp.252-257
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    • 2008
  • 산불은 산림이 울창해짐에 따라 대형화되고 화재에 의한 피해면적이나 그 피해액은 지속적으로 증가하고 있는 추세이다. 이러한 산불은 바람의 속도, 초지의 습도, 높이, 열량 등 많은 환경변수들의 차이에 따라 화염전파속도가 달라진다. 산불의 화염전파속도에 이러한 환경변수가 주는 영향을 정확히 예측한다면 산불 진화에 많은 도움이 되지만, 아직 정확한 영향에 대한 분석이 구축되어 있지 않다. 본 연구에서는 NIST에서 개발된 산불 화염전파 예측프로그램인 WFDS를 이용하여 다량의 실험 데이터를 보유하고 있는 호주의 초원화재실험조건을 기본 시뮬레이션 조건으로 설정하고, 수치해석결과와 실험결과를 비교하였으며, 이를 기준으로 초본의 높이와 바람속도의 변화에 따른 화염전파속도에 미치는 영향에 대해 알아보았다. 수치해석 결과 표면연료의 높이와 화염전파속도는 의 관계를 가지고, 바람의 속도에 따른 화염전파속도는 호주의 실험값에 비해 17%가량 하향 예측되었다. 또한 바람의 속도가 7.5m/s이상 높아지면, 열분해 된 가연물질이 빠른 바람의 속도에 의한 이동으로 인해 농도가 낮아지므로, 화염전파속도가 늦어진다.

벼에 대한 원소상 요오드 증기$(I_2)$의 직접오염경로 해석 실험 (An Experimental Study on the Direct Contamination Pathway of Elemental iodine Vapor $(I_2)$ for Rice Plants)

  • 최용호;임광묵;이창민;박효국;박두원;최근식;최희주;이한수;이창우
    • Journal of Radiation Protection and Research
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    • 제29권3호
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    • pp.165-172
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    • 2004
  • 피폭상자 내에서 벼를 생육단계별로 80 분 간 $I_2$ 증기에 피폭시키고 작물체 직접오염 관련 인자를 조사하였다. $I_2$ 증기의 경엽부 침적속도$(m\;s^{-1})$는 피폭시기에 따라 $1.4{\times}10^{-5}-1.3{\times}10^{-4}$의 범위로 생육 전반기 피폭시 비교적 낮았다. 이삭 침적속도는 $2.5{\times}10^{-5}-6.7{\times}10^{-5}$의 범위였다. 전체 작물체에 대한 침적속도는 $1.4{\times}10^{-5}-1.8{\times}10^{-4}$의 범위로 8월 18일(출수 시작후 7일) 피폭시 가장 높았다. 침적속도를 생육밀도 기준으로 나타내면 시기에 따른 변이 정도가 대체로 감소하였다. 기온, 일광 및 습도에 대한 이렇다할 침적속도의 경향성은 관찰되지 않았다. 요오드의 현미 전류계수는 $3.3{\times}10^{-5}-4.7{\times}10^{-4}$의 범위로 8월 23일 피폭에서 가장 높았다. 출수전 경엽부에 침적한 요오드도 상당량 현미로 전류하는 것으로 나타났다.

성장기 소녀에서 하악골 성장 변화와 발육 연령의 상호 관계에 대한 누년적 연구 (A LONGITUDINAL STUDY ON THE INTERRELATIONSHIP BETWEEN THE GROWTH CHANGE OF THE MANDIBLE AND DEVELOPMENTAL AGE OF GROWING GIRLS)

  • 김영준;손병화
    • 대한치과교정학회지
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    • 제22권3호
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    • pp.603-615
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    • 1992
  • This study was undertaken to investigate the interrelationship between the growth change of mandible and the developmental age of growing girls in the longitudinal data from 7 years to 15 years. The data were obtained from maturation stage of cervical vertebrae through the serial lateral cephalogram, height increment records which was taken at one year interval, menarche date through interview. On the basis of findings of this study, the following conclusions were obtained. 1. In general the growth of mandible (Ar-Pog, Ar-Go, Go-Pog) showed two peaks of growth velocity. 2. The maximum growth of mandible (Ar-Pog, Ar-Go, Go-Pog) almost appeared between stage 3 and stage 4 in maturation of cervical vertebrae. 3. It showed the tendency that the maximum increment of height appeared faster than that of mandible (Ar-Pog, Ar-Go, Pog-Go). 4. The maximum growth of height almost appeared between stage 2 and stage 3 in maturation of cervical vertebrae. 5. It showed the tendency that the menarche appeared later than the maximum growth of mandible (Ar-Pog, Ar-Go, Pog-Go). 6. The menarche almost appeared at stage 4, stage 5 in maturation of cervical vertebrae.

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Experimental Study of Heating Surface Angle Effects on Single Bubble Growth

  • Kim, Jeong-Bae;Kim, Hyung-Dae;Lee, Jang-Ho;Kwon, Young-Chul;Kim, Jeong-Hoon;Kim, Moo-Hwan
    • Journal of Mechanical Science and Technology
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    • 제20권11호
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    • pp.1980-1992
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    • 2006
  • Nucleate pool boiling experiments were performed using pure R11 for various surface angles under constant heat flux conditions during saturated pool boiling. A 1-mm-diameter circular heater with an artificial cavity in the center that was fabricated using a MEMS technique and a high-speed controller were used to maintain the constant heat flux. Bubble growth images were taken at 5000 frames per second using a high-speed CCD camera. The bubble geometry was obtained from the captured bubble images. The effects of the surface angle on the bubble growth behavior were analyzed for the initial and thermal growth regions using dimensional scales. The parameters that affected the bubble growth behavior were the bubble radius, bubble growth rate, sliding velocity, bubble shape, and advancing and receding contact angles. These phenomena require further analysis for various surface angles and the obtained constant heat flux data provide a good foundation for such future work.